Field of the Invention
The present invention relates to an original holding apparatus which holds an original, an exposure apparatus, a method of manufacturing an article, and an original holding method.
Description of the Related Art
One of apparatuses used in the manufacturing process (lithography process) of a semiconductor device or the like is an exposure apparatus which transfers the pattern of an original to a substrate during scanning slit light on the substrate. To improve productivity, the exposure apparatus needs to increase the acceleration of an original stage which holds the original. However, if the acceleration of the original stage is increased, a force applied between the original stage and the original by the acceleration of the original stage exceeds a force for holding the original by the original stage, and a slip may occur between the original and the original stage. To prevent this, Japanese Patent Laid-Open No. 2011-23425 has proposed an original stage in which the force for holding an original is increased by vacuum-chucking both the upper and lower surfaces of the original.
The original stage disclosed in Japanese Patent Laid-Open No. 2011-23425 includes fixing unit which fix second holding unit with respect to first holding unit so that the relative position of the first holding unit for vacuum-chucking the lower surface of the original, and the second holding unit for vacuum-chucking the upper surface of the original does not change during scanning exposure of the substrate. However, according to Japanese Patent Laid-Open No. 2011-23425, when the fixing unit fixes the second holding unit on the original stage in a state in which the chucking force of the first holding unit and the chucking force of the second holding unit are set to be equal to each other, the second holding unit may be displaced with respect to the first holding unit so as to damage the original. Japanese Patent Laid-Open No. 2011-23425 does not disclose a technique of controlling the chucking force of the first holding unit and the chucking force of the second holding unit to reduce the possibility at which an original is damaged when fixing the second holding unit by the fixing unit.